package com.atguigu.gulimall.product.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;
import com.atguigu.gulimall.product.service.CategoryBrandRelationService;
import com.atguigu.gulimall.product.vo.Catelog2Vo;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.Caching;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {
    @Autowired
    CategoryBrandRelationService categoryBrandRelationService;
    @Autowired
    StringRedisTemplate redisTemplate;
    @Autowired
    RedissonClient redisson;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1 查出所有的分类
        List<CategoryEntity> entities = baseMapper.selectList(null);
        //2 组装成父子的树形结构
        //2.1) 找到所有的一级分类
        List<CategoryEntity> levelMenus = entities.stream().filter(categoryEntity -> categoryEntity.getParentCid() == 0)
              .map((menu)->{
                  menu.setChildren(getChildrens(menu,entities));
                  return menu;
              })
              .sorted((menu1,menu2)->{
                  return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
              })
              .collect(Collectors.toList());
        return levelMenus;
    }

    @Override
    public void removeMenuByIds(List<Long> longs) {
        //TODO 检查当前删除的菜单，是否被别的地方引用
        baseMapper.deleteBatchIds(longs);
    }

    @Override
    public Long[] findCatelogPath(Long catelogId) {
        List<Long> paths = new ArrayList<>();
        List<Long> parentPath =  findParentPath(catelogId,paths);
        Collections.reverse(parentPath);
        return parentPath.toArray(new Long[parentPath.size()]);
    }
    /*级联更新所有关联的数据*/

//    @Caching(evict = {
//       @CacheEvict(value= "category",key = "'getLevel1Categorys'"),
//       @CacheEvict(value= "category",key = "'getCatalogJson'")
//
//    })
    @CacheEvict(value= "category",allEntries = true)
    @Transactional
    @Override
    public void updateCascade(CategoryEntity category) {
        this.updateById(category);
        categoryBrandRelationService.updateCategory(category.getCatId(),category.getName());
        //数据库改变同时删除缓存
        //redis.del("catalogJSON")

    }
    //每一个需要缓存的数据我们都来指定要放到哪个名字的缓存【缓存的分区（按照业务类型）】
    @Cacheable(value= {"category"},key = "#root.method.name",sync = true)      //代表当前方法的结果需要缓存，如果缓存中有，方法不用调用，如果缓存没有，将结果写到缓存
    @Override
    public List<CategoryEntity> getLevel1Categorys() {
        List<CategoryEntity> categoryEntities = baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));

        return categoryEntities;
    }

    @Cacheable(value= "category",key = "#root.methodName")
    @Override
    public Map<String, List<Catelog2Vo>> getCatalogJson() {
        System.out.println("查询了数据库");
        /**
         * 将数据库的多次查询变为一次
         */
        List<CategoryEntity> selectList = baseMapper.selectList(null);

        //查出所有 1 级分类
        List<CategoryEntity> level1Categorys =  getParent_cid(selectList,0L);

        //封装数据
        Map<String, List<Catelog2Vo>> parent_cid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            List<CategoryEntity> categoryEntities = getParent_cid(selectList,v.getCatId());
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //将当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList,l2.getCatId());
                    if(level3Catelog != null){
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            //封装成指定的格式
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);

                    }


                    return catelog2Vo;
                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        return parent_cid;
    }

    //    @Override
    public Map<String, List<Catelog2Vo>> getCatalogJson2() {
        //给缓存中放json字符串，拿出的json字符串，还用逆转为能用的对象类型：【序列化与反序列化】
        //加入缓存逻辑,缓存中存的数据是json字符串
        //JSON跨语言，跨平台兼容
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if(StringUtils.isEmpty(catalogJSON)){
            //缓存种没有，查询数据库
            Map<String, List<Catelog2Vo>> catalogJsonFromDb = getCatalogJsonFromDbWithRedisLock();
            //查到的数据再放入缓存，将对象转为json放在缓存中
            String s = JSON.toJSONString(catalogJsonFromDb);
            redisTemplate.opsForValue().set("catalogJSON",s,1,TimeUnit.DAYS);
            return catalogJsonFromDb;
        }
        //转化为我们指定的对象
        Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>(){});
        return result;
    }

    //从数据库查询被分类整个数据  使用Redis的高级分布式锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedissonLock() {
        //占分布式锁，去redis占坑
        RLock lock = redisson.getLock("catalogJson-lock");
        lock.lock();
//        String uuid = UUID.randomUUID().toString();
//        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", "111");
//        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", uuid, 300, TimeUnit.SECONDS);
            System.out.println("获取分布式锁成功。。。");
            //加锁成功....  执行业务
            //设置过期时间，必须和加锁是同步的，原子的  redisTemplate.expire("lock",30,TimeUnit.SECONDS
            Map<String,List<Catelog2Vo>> dataFromDb = null;
            try{

                dataFromDb =  getDataFromDb();
            }finally {
                lock.unlock();
//                String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
//                        "    return redis.call(\"del\",KEYS[1])\n" +
//                        "else\n" +
//                        "    return 0\n" +
//                        "end";
//                Long lock1 = redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class),
//                        Arrays.asList("lock"), uuid);
            }
            return getDataFromDb();



    }

    //从数据库查询被分类整个数据  使用分布式锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedisLock() {
        //占分布式锁，去redis占坑
        String uuid = UUID.randomUUID().toString();
//        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", "111");
        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", uuid, 300, TimeUnit.SECONDS);
        if(lock){
            System.out.println("获取分布式锁成功。。。");
            //加锁成功....  执行业务
            //设置过期时间，必须和加锁是同步的，原子的  redisTemplate.expire("lock",30,TimeUnit.SECONDS
            Map<String,List<Catelog2Vo>> dataFromDb = null;
            try{

               dataFromDb =  getDataFromDb();
            }finally {

                String script = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
                        "    return redis.call(\"del\",KEYS[1])\n" +
                        "else\n" +
                        "    return 0\n" +
                        "end";
                Long lock1 = redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class),
                        Arrays.asList("lock"), uuid);
            }
            return getDataFromDb();

        }else{
            System.out.println("获取分布式锁失败。。。");
            try {

                Thread.sleep(200);
            }catch (Exception e){
                e.printStackTrace();
            }
            //加锁失败。。。重试  自旋的方式，  递归的方式
            return getCatalogJsonFromDbWithRedisLock();
        }


    }

    private Map<String, List<Catelog2Vo>> getDataFromDb() {
        //加锁，防止 缓存击穿
        //只要是同一把锁，就能锁住需要这个锁的所有线程
        //1、synchronized (this)：SpringBoot所有的组件在容器中都是单例的
        //TODO 本地锁，synchronized (this) JUC(Lock) 在分布式情况下，想要锁住所有，必须使用分布式锁

        //得到锁之后，我们应该再去缓存中确定一次，如果没有才需要继续查询
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if(!StringUtils.isEmpty(catalogJSON)){
            //转化为我们指定的对象
            Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>(){});

            return result;
        }
        System.out.println("查询了数据库");
        /**
         * 将数据库的多次查询变为一次
         */
        List<CategoryEntity> selectList = baseMapper.selectList(null);

        //查出所有 1 级分类
        List<CategoryEntity> level1Categorys =  getParent_cid(selectList,0L);

        //封装数据
        Map<String, List<Catelog2Vo>> parent_cid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            List<CategoryEntity> categoryEntities = getParent_cid(selectList,v.getCatId());
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //将当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList,l2.getCatId());
                    if(level3Catelog != null){
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            //封装成指定的格式
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);

                    }


                    return catelog2Vo;
                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));


        String s = JSON.toJSONString(parent_cid);
        redisTemplate.opsForValue().set("catalogJSON",s,1,TimeUnit.DAYS);
        return parent_cid;
    }

    //从数据库查询被分类整个数据  使用本地锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithLocalLock() {
        //加锁，防止 缓存击穿
        //只要是同一把锁，就能锁住需要这个锁的所有线程
        //1、synchronized (this)：SpringBoot所有的组件在容器中都是单例的
        //TODO 本地锁，synchronized (this) JUC(Lock) 在分布式情况下，想要锁住所有，必须使用分布式锁
        synchronized (this){
            //得到锁之后，我们应该再去缓存中确定一次，如果没有才需要继续查询
            return getDataFromDb();

        }


    }

    private List<CategoryEntity> getParent_cid(List<CategoryEntity> selectList,Long parent_cid) {
        List<CategoryEntity> collect = selectList.stream().filter(item -> item.getParentCid() == parent_cid).collect(Collectors.toList());
        return collect;
//        return baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", v.getCatId()));
    }


    private List<Long> findParentPath(Long catelogId,List<Long> paths){
        //收集当前id
        paths.add(catelogId);
        CategoryEntity byId = this.getById(catelogId);
        if(byId.getParentCid()!=0){
            findParentPath(byId.getParentCid(),paths);
        }
        return paths;
    }

    private List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){
        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid() == root.getCatId();
        }).map(categoryEntity -> {
            //递归寻找子菜单
            categoryEntity.setChildren(getChildrens(categoryEntity, all));
            return categoryEntity;
        }).sorted((menu1, menu2) -> {
            //菜单的排序
            return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());
        return children;
    }






















}